1. Field of the Invention
The present invention relates to a blade element of a turbomachine, in particular of a gas turbine, preferably of an aero engine, having a fastening element, with which the blade element is arranged in a receptacle of the turbomachine, wherein, in the region of the fastening element, the blade element has a core region and an envelope region which at least partially envelops the core region, and wherein the core region is formed from a blade base material which is more brittle than the envelope material of the envelope region. Moreover, the present invention relates to a corresponding turbomachine having such a blade element and also to a turbomachine, in which a blade element is arranged with a fastening element in a receptacle of a turbomachine. Furthermore, the present invention relates to corresponding processes for producing blade elements and turbomachines.
2. Discussion of Background Information
DE 10 2005 054 172 A1, the entire disclosure of which is incorporated by reference herein, discloses a blade of a turbomachine, in which the blade root of the blade, which is made of a slightly ductile to brittle material, for example of a TiAl material, is provided with a ductile compensation layer, in order to reduce stress peaks upon contact of the blade root with a blade root receptacle in which the blade is arranged, so that the brittle material of the blade is protected against cracking or destruction by fracture. Alternatively, a corresponding blade root could also be produced observing very narrow tolerances, or appropriate spherical shapes could be formed in order to avoid even the occurrence of stress peaks. However, these measures are very complex, and therefore the provision of ductile compensation layers is an advantageous alternative.
However, in the case of the compensation layers, there is the problem that, under certain circumstances, the service life of the compensation layers is very low and, despite the provision of appropriate compensation layers, the stress peaks may still not be sufficiently avoided or reduced.
Accordingly, it is desirable to be able to achieve an improved reduction of stress peaks over a longer period of time in the case of components of a turbomachine which are formed from slightly ductile or brittle materials, for example blades made of TiAl materials, so that the production tolerances for these components can be reduced further and the service life is increased. In addition, it is desirable to be able to dispense with the provision of spherical structures for avoiding stress peaks. Furthermore, it is desirable to be able to avoid having to make modifications to the base materials used for solving the bearing problems, for example avoiding the cracking of blades when blade roots are arranged in blade root receptacles. Alternatively, it is desirable to make a more variable use of base materials possible, in order to thereby increase the freedom of design.